Quick and Dirty Mosquito Trap





Introduction: Quick and Dirty Mosquito Trap

About: I'm an Electrical Engineer who dabbles in just about everything. By trade, I'm a controls engineer and design machines for the largest manufacturing plants in the world. At home, I make a lot of embedded sys...

Mosquito season is fast approaching - make a simple trap for cheap. The theory is that the light attracts mosquitos and the fan sucks them into the bag (usually shredding them in the process). This instructable is in experimental phase and will be updated as we go (see the Science step). I release it here as a neat community science project.I hope that folks will take the base idea, add a little twist, and then get back to me with the results. I will feature people's builds and improvements with full credit to the authors so other folks can learn from each other's mistakes and successes.

This build is darn simple on purpose. I get sick of instructables that require fancy tools like laser cutters, 3D printers, and CNC machines. I, myself, was tempted to make this super elegant with a CNC-cut or 3D printed box, but I didn't. Not everyone has the money for or access to fancy tools, and I wanted to respect that. Of course, you can fancify this to your heart's content, but you don't need to.

The only tool you need for this project is a soldering iron, and you can even get around that just twisting wires. A set of wire cutters is recommended as well, but you can accomplish the same thing with a pocket knife or a razor blade and a bit of caution.

Something I mention later but want to stress here as well: This trap will kill bugs (and possibly geckos) other than mosquitos. Think about adding a grating just large enough for mosquitos and ONLY turn this on when you are outside nearby. Use it like you might use a citronella candle: don't use it 24/7 when you don't need it.

I try to keep track of people's comments and respond to them. Before commenting on something, take a look at the "Science and Comment Feedback" step and see if I address your concern/idea ;)

Step 1: Materials

You will need a 12V power supply (you don't need anything fancy or high amperage), a standard computer fan with LEDS built in, a mesh bag with a 6 inch wide mouth (mine is a filter bag used in fish tanks), wire, superglue, and possibly magnets if you want to mount this to something steel. You will also need a long piece of scrap anything or a popsicle stick.

Solder and heat shrink are recommended, but not required (you can twist and tape around wires if needed, it's just not as sturdy).

Step 2: Superglue

Superglue (or hot glue...or epoxy...) your piece of scrap to the front of the fan on one of the corners. Superglue optional magnets to the other end. I actually added a second set so it would mount better to my airconditioner and not tip over.

Step 3: Solder

Cut two lengths of wire that are long enough to reach between the power outlet and where you plan to mount your trap and strip the ends. Lop the connectors off your 12V supply and your fan. Then solder the positive of your supply to one of the new wires and that wire to the positive of the fan. Do the same with the negative wires.

Note that red is positive and black is negative. There may also be a third wire on the fan that is usually yellow. You can snip that off and ignore it.

Tape or heat shrink the exposed wires. It is wise to add a bit of stress relief by making a small coil of wire and then fixing it to your mount with a zip tie, glue, or tape. This will keep your wires from getting pulled apart as easily.

Step 4: Fit the Bag

Simply slip the bag over the back side of the fan. You may decide to use rubber bands or tape to hold it in place.

Step 5: Mount and Enjoy!

Mount your new creation with magnets, tape, or a couple nails. Now, just plug it in and enjoy fewer biting bugs!

Step 6: Science and Comment Feedback

A few commenters are questioning whether or not mosquitos are attracted to light and whether or not this trap will work. Great question. Answer? I don't currently know, but I believe it will work. I based this idea around seeing many mosquitos hanging out on the screens of closed windows at night last summer. When it warms up here and the mosquitos are out, I will give this a more extensive try - if it doesn't work well, I will happily brand it as "Failed Quick and Dirty Mosquito Trap" so others may learn from my mistakes. I am a scientist and will turn on a dime if things don't meet a hypothesis.

A few people have suggested IR LEDs in place of the colored ones. As luck would have it, I do have a 12V IR spotlight we can try. My guess, however, is that it will do very little. IR LEDs emit a wavelength that is different than the ones things emit when hot. What would work better is to place a power resistor in front of the fan as a heating element. I will try both in a couple months and post the results :)

That said, you can turn this into a great science project and see what you can do with it. Do different colors attract more or different kinds of bugs? Does it work better if you mount it in a tube so the light only shows out one side? Will a slow stream of CO2 from a paint ball canister make it work better? How about if you stick a piece of worn, sweaty undies by the fan to see if body odor is an attractant? (Kinda gross, but hey, it's for SCIENCE!)

Try things, message me your results with pics, and I'll post them here with full credit to you and links to your Instructables profile.

On of the commentors sent me this: https://www.instructables.com/id/How-to-make-a-1-Mo...
It's a similar concept but with a large box fan. It would be kind of neat if folks combine his idea with mine and threw LEDs and/or a heat source to create a super mosquito trap. It would be interesting to see if it works better or worse :)

Step 7: Disclaimer and Front Grating

Other users brought it to my attention that this trap will kill harmless insects and possibly animals like geckos that are attracted by light.

This was not something I had thought about. Where I live in Colorado, the majority of flying insects that hover around lights are mosquitos and some moths (and we definitely don't have geckos).

It may be a very good idea to put a form of "reverse grating" over the front of the trap; something with holes large enough for mosquitos to pass through but small enough to stop larger insects and animals from getting hurt.

Also only turn this trap on when you are on the back porch and actually need it (treat it like a cintronella candle maybe). No sense shredding animals and bugs that can't hurt you while you are indoors.



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Thank you for making this without the aid of laser beams and Arduinos. It seems people are forgetting very quickly that our hands can make things, too.

Don't get me wrong,. I would love to own some high tech toys - they're incredibly useful - but nothing beats the satisfaction in making something from scratch, on your own, with stuff you have hanging about.

I built a hot wire foam cutting table last week for free! Scrap wood, a piece of found aluminum bar, a bit of nichrome wire someone gave me ages ago...it's awesome!

Neat idea! And good job explaining to people that it doesnt have to be fancy.

nice no-fancy-tools thing. although the people in the ad department of the site may dissagree... 3d printer ad while i type lol

cool! but if it shredds bugs, what about a plastic bag or duck tape bag?(bag made of duck tape)

I notice several people are asking the same question I'm about to ask, though there is a reason I'm asking.

Brydon points out that mosquitos are not attracted to light, which is true. Rather, aside from the chemical commentary he uses, they are also attracted to heat--or rather Infrared light which is not something you'd find on a computer case fan. Which leads to the question itself as to how effective your gadget is against mosquitos themselves.

You appear to be basing your idea on the fact that the bug zappers so readily available now are relatively effective against mosquitos--as well as other bugs, obviously. The reason isn't the necessarily the light itself, which is an ultraviolet fluorescent tube usually, but rather the heat that the tube puts out. The UV attracts other pest insects that are harmless but annoying when they land on and around people and food outdoors (hey, they have to eat too, you know). But I'll also note that it can attract bats that will be flying through the space to catch some of those insects before they get zapped. That can be frightening to someone who isn't expecting it.

So again, how effective is your lighted bag-fan against mosquitos themselves?

4 replies

To be honest, I'm not completely certain. I based the idea around seeing handfuls of mosquitos hanging on on the screens of closed windows last summer. When it hits around 90 degrees out here and the mosquitos are out in force (next to none are out now), I will give it a shot.

If I find it doesn't work well for mosquitos, I will happily rebrand this as "Failed Quick and Dirty Mosquito Trap" so folks can learn from my mistakes. I may also make changes such as a simple heater resistor to make it more effective.

I have to point out that I, too, may be wrong. I read the article linked by another commenter which suggests that heat may be just as ineffective. There may be no truly effective technology device other than either 'smothering' human and animal CO2 emissions with vapors repellant to the mosquito or somehow inviting bats to the party along with the so-called 'mosquito hawks' which may be what you've been catching so far. Said article made it quite clear that bug zappers, if anything, increased the population of biting mosquitos by reducing the population of natural predators.

I have to sadly inform you that mosquito hawks are not. It's the most depressing fact that I've learned - they're actually called crane flies, and they do not eat mosquitoes :(

Bats, OTOH, do. Bats are the best! <3

And sadly bats do not eat many mosquitoes either. It's a bit of a myth. Like bug zappers, bats are much better at eating big juicy moths and leaving the minuscule mosquitoes alone. Mosquitoes make up less than one percent of a bat's diet. But I still agree that they are the best.

Well the only problem I see is that, **mosquitoes aren't attracted to light**, though most bugs are (good ones, that eat mosquitos included) Those little blood suckers are attracted to CO2, they home in on Mammals that way. Gee, ever get bitten at night, in the dark !? There are CO2 based, traps out there.

And because light attracts other bugs, you cannot use it out doors. Bugs will just keep coming, and coming and......And I wouldn't want the kids around when a good sized moth flies into the chopper ! So this is one of those projects that while seemingly a good idea, in practice, doesn't work.

9 replies

I am not sure if there might be variability between species, but most definitely mosquitos in my parts of the world are attracted to light, even common incandescent houselights. When you step in a room where the light was on for a while, you'll see plenty outside buzzing against the windows. However, I agree that they are attracted to light, but not as much as moths and some other insects. We used to have an electric trap with UV lights. While effective, it ended up killing many more than more moths than mosquitos.

I think it's a great idea that will work awesome "in practice" in my garage where I want to chop up every type of bug. Also gonna make one for the house. On movie night as soon as we shut off all the lights sure enough, 5 mins in a bug lands on the screen.

This isn't correct. Mosquitos have in lab condition to be highly attracted to certain wave lengths. Green is the best or around 500nm

High school kids in Lesotho created an elegant and very effective device to trap malarial mosquitoes. Make a small slatted box (slats must be angled 45 degrees or so. Place a small solar panel on top. Connect it to a fairly slow running fan. Spray a small amount of insecticide in if you have it. Place smelly socks inside the box. (any worn, sweaty clothing will do). Mosquitoes are drawn to the sweat, cannot exit the box, and eventually die in the fan or of exhaustion, or from the poison.

This sounds pretty interesting, do you have a source you can link to?

I would disagree with you when you say mosquitos aren't attracted to light. During the summer months, I will have several camped out on the screens of my windows at night when the windows are closed and no CO2 or other chemical attractant can pass through them. That is how I originally came up with the idea.

There are definitely CO2 traps available on the market, but they are rather expensive and physically large eyesores.

I added a bit a few minutes ago about placing a front grating to keep moths and insects larger than mosquitos out of the trap.

If you are standing in your house, with mosquitos on the screen, you have CO2 , yours.

If you use this outside, you will ATTRACT bugs to your location. Use open flame for outside lighting when possable.

Yea the FIRST thing I do while camping is get a nice smoky fire going and stand downwind in the smoke for a while ... best skeeter repellent there is I do this and get bitten far less than with using bug repellent, although if you are in an area with much larger than normal skeeter population Id use repellent as well.

Again, the windows were closed thus ruling out your CO2 idea as the attractant in this case. I agree with you that CO2 is probably a stronger attractant than light, but CO2 traps are messy (see yeast traps) or expensive and large.